Overview

The Detour Lake project is located on the northern most, relatively under-explored, Abitibi Greenstone Belt in northeastern Ontario. It encompasses 265 square kilometres, including the Detour Lake deposit, which contains an in-pit gold resource of 13.2 million ounces (measured and indicated resource of 10.8 million ounces and inferred resource of 2.4 million ounces) based on a detailed engineered pit design. The Detour Lake deposit is situated in the area of the former Detour Lake mine, which was operated by Placer Dome and produced 1.8 million ounces of gold from 1983 to 1999. In addition, Detour Gold has a 50% interest in Block A.

The Detour Lake project is approximately eight kilometers west of the Ontario-Quebec border and 180 kilometers northeast of Cochrane, Ontario. Access to the property is available via the Detour Lake mine road, an extension of Highway 652 from Cochrane, as well as by air to the site's 1.6 kilometer gravel airstrip.

In April 2008, Detour Gold entered into an agreement with Goldcorp Canada ("Goldcorp") to exercise its option for a 100% interest in the Detour Lake Mine Property (Mine Option"), which hosts the current resource. The transaction is expected to close in the third quarter of 2008. At that time, Detour Gold will assume all of Goldcorp's liabilities and obligations relating to the Mine Option. Part of the exploration properties and the Mine Option are subject to a 2% NSR to Newmont and a 1% NSR to Goldcorp.

Detour Lake project - Location & general geology
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Project History

The Detour Lake mine was discovered by Amoco Petroleum Limited in 1974. Most of the past exploration and mine development has been carried out by four main operators, including Amoco, Campbell Red Lake Mines, Placer Dome and Pelangio Mines Inc.

Amoco conducted the initial work between 1974 and 1979, followed by Campbell between 1979 and 1987, Placer Dome between 1987 and 1999 and Pelangio between 1999 and 2006. A minor amount of work was also completed by a number of small companies, such as Global Energy Limited, Gowest Amalgamated and Destor Resources Exploration.

The first mining activity at the property was by Campbell between 1983 and 1986, utilizing open pit methods. Campbell and then Placer Dome mined the deposit by underground methods until July 1999. Details regarding the original open pit are limited, but indications are that small-scale equipment and a selective mining approach were used. The open pit extended to a depth of approximately 120 meters with an estimated strip ratio of 4.5:1 (excluding low grade ore). Underground mining was conducted from the 120 meter level to approximately 785 meter below surface. Access for mining was provided by a 600 meter shaft located approximately 150 meter west of the open pit, as well as a series of ramps extending to the 785 meter level.

Past production totalled approximately 1,764,986 ounces of gold from the milling of just over 14.3 million tonnes of ore at an average recovered grade of 3.82 g/t, including 5.2 million tonnes grading 2.57 g/t (430,516 ounces) from the open pit and 9.1 million tonnes grading 4.98 g/t (1,464,431 ounces) from underground. Average mill recoveries were 93.2 %.

From 2004 to 2006, Pelangio drilled 127 holes totalling 29,780 meters. Results from this recent work outlined a near-surface gold resource (0 to 250 metres) of 160,000 ounces in the indicated category and 850,000 ounces in the inferred category.

Geology & Mineralization

The Detour Lake project is located within the northwestern portion of the Abitibi Greenstone Belt in the Superior Province of the Canadian Shield. It is centred on the contact of the Stoughton-Rocquemaure volcanic assemblages and the Porcupine sedimentary sequence. The Stoughton-Rocquemaure volcanic assemblage is comprised primarily of massive and pillowed mafic volcanics and minor ultramafics, while the Porcupine assemblage is comprised of a clastic sedimentary package consisting of conglomerate, greywacke and argillite.

The Sunday Lake Deformation Zone ("SLDZ") is a major east-west structure in the area located on the northern contact of the Porcupine sediments. It is defined by a deeply mylonitized and mineralized siliceous alteration zone, referred as the Chert Marker Horizon ("CMH"), which marks the contact between the basaltic and ultramafic terranes.

The bulk of the gold mineralization at Detour Lake is found in the hanging wall of the CMH. The hanging wall is composed of a thick assemblage of iron-rich tholeiitic mafic flows that are predominantly massive to pillowed, with minor rhyolitic flows and tuffs.

The mineralized east-west corridor forms a 200 m wide (locally up to 350 m) zone that is characterized by swarms of steeply dipping mineralized quartz veining splaying off the SLDZ. The richest gold mineralized zones are commonly associated with increased biotite alteration, shearing, narrow quartz veining and pyrite or pyrrhotite. Local zones of strong brecciation with sulphide infilling have also been recognized along with chalcopyrite, telluride minerals and visible gold. Visible gold is usually found as specks, clusters or fracture coatings, and its abundance may be associated with the chlorite and chalcopyrite content of the vein. Pillowed flows or hyaloclastites are the preferred hosts to mineralized zones. In the area of the Calcite Zone, the gold mineralization is closely associated with weak potassic and strong carbonate alteration and often contains carbonate in veinlets and quartz veins.

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Mineral Resources

On July 2, 2008, Detour Gold reported a mineral resource update (previous one was in December 2007) that included the historical drilling, Phase I drill results (49,322 metres), 51% of Phase II drill results (73,469 metres). The results showed a 125% increase in measured and indicated gold resources from 4.8 million ounces to 10.8 million ounces while inferred gold resources have decreased 20% from 3.0 million ounces to 2.4 million ounces.

The proposed open pit extends 2.7 kilometres in length and up to 650 metres in depth. There is excellent potential for additional mineralization along strike, especially west of the Calcite Zone for several kilometres. The mineralized system has also not been fully tested to the north in the hanging wall outside of the main 200 metre wide corridor. The deposit remains open below the former open pit where significant gold mineralization was intersected in the footwall of the chert marker horizon (CMH) (i.e. hole DG-07-194A).

Based on a cut-off grade of 0.50 g/t gold and a gold price of US$700 per ounce, the in-pit resources included in a detailed engineered pit design are shown below (Table 1).

The mineral resource increase is largely due to:

• An additional 73,000 metres of drilling completed throughout the deposit, with a focus in the Calcite Zone (western end); also, the 40 metre by 40 metre drill spacing (from a 80 metre drill spacing) has successfully improved the continuity of the deposit;
• Discovery of more mineralized zones in the hanging wall, north of the known 200 metre wide corridor;
• Addition of known mineralization that was previously drilled (prior to Detour Gold) into the new pit shell (below the previous 2007 US$575 pit shell);
• Increase in search radius for indicated and inferred resources as a result of better continuity; and
• Gold price increase from US$575 to US$700 per ounce with a cut-off grade of 0.50 g/t.

2008 Detour Lake Block Model
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Mineral Resource Estimate Method

The current block model was prepared by Thon Consulting ("Thon") of Smithers, British Columbia. Mineral resources were estimated within a Lerchs Grossman ("LG") optimized pit shell based on the concept of a large-scale open pit with the following pit parameters to establish the cut-off grade: gold price of US$700 per ounce, $5.50/t for milling, $1.58/t for ore and waste mining and $1.00/t for general and administration (G&A), gold recoveries of 92%, US$ exchange rate of 1.10, and pit slopes of 55 degrees. Pit parameters were provided by the engineering firm of BBA Inc. ("BBA") of Montréal, Québec.

The block model mineral resources falling within the LG optimized pit shell were subsequently audited by Watts, Griffis and McOuat Limited ("WGM") and validated by BBA before proceeding with the engineered pit design. WGM has concluded from their work and review that the search distance for both the indicated and inferred categories can be increased from 20 to 30 metres and from 40 to 50 metres, respectively, as a result of improved continuity of the deposit.

Gold assays are capped at 20 g/t as per the historic capping at the former mine and the December 2007 mineral resource estimate. Preliminary and ongoing independent geostatistical studies based on all drill results to date indicated that a higher capping grade could be used in the resource estimate.

The mineral resource estimate within the US$700 LG pit shell (using a cut-off grade of 0.50 g/t gold) on 10X5X10 meter blocks is presented below (Table 2). The overall waste to ore stripping ratio is 5.7.

Mineral Resources in Detailed Engineered Pit Design

The optimization and designs of the US$700 pit by BBA (Base Case -- Table 1) were based on the block model supplied by Thon. For the Base Case, BBA used the economical input parameters presented above. The design pit included an operational haul road and pit slope as per recommendations from Golder Associates; benching arrangement and configuration; and smoothing of pit walls and berms.

The mine operating cost established by BBA is based on a preliminary mine schedule at a mining rate of 30,000 tonnes per day (tpd) for the first two years of operation and 60,000 tpd in the subsequent years. Although the preliminary estimates for projected costs (reported on page 2) are believed to be realistic, as they are based on projects of similar (or lesser) production rates, they should be considered preliminary and subject to a high degree of risk. BBA used an overall gold recovery rate of 92% (metallurgical testwork completed by Melis Engineering Ltd. yielded recoveries ranging from 91% to 95%).

The following are the main open pit design parameters used by BBA:

1. Pit ramp of 10% gradient and 32 metres wide to support 2-way haulage for 218 tonne capacity;
2. Inter-ramp angles are 53o to 56 o in the hanging wall and 49 o to 53o in the footwall based on recommendations by Golder; and
3. Mining dilution is not incorporated in the resource estimate.

Based on those design parameters described above, BBA generated an engineered pit containing the mineral resources shown in Table 1, which is now considered the Base Case. The overall waste to ore stripping ratio is 6.29.

A summary table of the in-pit resources by cut-off grades from 0.3 g/t Au to 0.9 g/t Au is presented in the table below (Table 3) for the $700 engineered pit. The in-pit resources between 0.30 g/t and 0.5 g/t Au will be stored on a low grade stockpile located near the primary crushing plant.

(1) The mineral resources are classified as measured, indicated and inferred, and comply with the CIM mineral resource definitions referenced in National Instrument 43-101.
(2) Base case assumes a gold price of US$700/oz gold and $US exchange rate of $1.10.
(3) Mineral resources that are not mineral reserves do not have demonstrated economic viability.
(4) The quantity and grade of reported inferred resources in this estimation are conceptual in nature and there has been insufficient exploration to define these inferred resources as an indicated or measured resource and it is uncertain if further exploration will result in upgrading them to an indicated or measured resource category.

BBA also conducted a sensitivity analysis to generate a resource estimate with no capping. As expected, the result of the analysis as shown below (Table 4) indicated a significant increase in the gold grade for all categories.

Preliminary Mining Schedule

A preliminary mining schedule was prepared for the development of the Detour Gold project and is presented below (Table 5). The mining schedule is based on a mining rate of 30,000 tpd for Year 1 and Year 2, followed by an increase to 60,000 tpd for subsequent mining years until the end of the mine life. The schedule is created using five (5) mining phases, about 3 to 4 years per phase including a starter pit to allow for a higher average grade and a lower stripping ratio to maximize the return on the investment. A cut-off grade of 0.50 g/t is used and the schedule consists of all mineral categories (i.e. measured, indicated and inferred). The preparation of this preliminary mining schedule does not include mining dilution and gold recovery factor.

Pit Slope Design Upside Potential

Subsequent to the mineral resource update of July 2, 2008, results from acoustic televiewer (ATV) surveys carried out in three exploration holes targeting the footwall slopes indicated that the pit slopes could be steepened to 53 degrees from 49 degrees in certain portions of the footwall. These improvements will be incorporated in the final pit design of the feasibility study currently underway.

Further improvements are expected, especially at the west end of the deposit, as the Company completes its infill drill program (remaining Phase II and Phase III) and incorporates them in the US$700/oz engineered pit design.

Detour Gold August 2008 Technical Report -   19M

Detour Gold January 2008 Technical Report -   10KB

Project Development

Release of the remaining Phase II drill results (approximately 75,000 metres) is expected over the next six months. With the encouraging results obtained this far, another 30,000 metres of drilling (Phase III) has been added to properly continue the infill of the deposit on a 40 metre by 40 metre grid and to expand the deposit to the west of the Calcite Zone. Over 20,000 metres of this program has been completed as of the end of July 2008.

The Company is making good progress on its feasibility study. Detour Gold plans to order its long-lead items (i.e. SAG and ball mills) in the third quarter of 2008. Ongoing optimization studies are currently underway for the design pit and process design flowsheet. Work is underway for the Environmental Impact Assessment, which is expected to be completed by in 2009.

Cautionary note to U.S. investors concerning estimates of inferred mineral resources: This website uses the term "inferred mineral resources". We advise U.S. investors that while this term is recognized and required by Canadian regulations, the U.S. Securities and Exchange Commission does not recognize it. "Inferred mineral resources" have a great amount of uncertainty as to their existence, and great uncertainty as to their economic and legal feasibility. It cannot be assumed that all or any part of inferred mineral resources will ever be upgraded to a higher category. Under Canadian rules, estimates of inferred mineral resources may not form the basis of a feasibility or other economic study. U.S. investors are cautioned not to assume that any part or all of an inferred mineral resource exists or is economically or legally mineable.